The Relationship between Bud Dormancy and Carbohydrates, Nitrogen in Mulberry Tree

By 林進財, 楊耀祥, Jinn-Tsair Lin and Yau-Shiang Yang

Abstract

以3年生盆栽台桑2號桑樹植株為供試材料，利用其單芽扦插及剪留10個芽體之單枝盆栽植株，置25℃恆溫環境下，調查芽體休眠深度與碳水化合物及氮素之關係。由試驗結果發現，台灣桑樹之芽體自10月下旬進入休眠，11月上旬至下旬為深休眠期，12月上旬以後開始覺醒。\ud
當芽體進入休眠時，其枝條全糖含量隨著休眠深度之推移而增加，在芽體休眠覺醒時，則大幅增加；澱粉含量亦隨著休眠深度而增加。深休眠時期達最高，在休眠覺醒時則下降。另外，在休眠期間，其枝條蛋白態氮無甚大變化，在覺醒時，呈小幅度增加；非蛋白態氮在進入休眠後，其含量最低，覺醒時則驟然上升。以氰氨基化鈣催芽則可提高萌芽率。Bud dormancy state of 3 year- old mulberry trees Taisan 2 (Morus alba L. var. asidosa G. cv. Taisan 2) were investigated by using the method of single bud cutting and ten buds potted plants under a 25 ℃ condition for 15 days during the fall and winter in Taichung. Most of buds fell into deep dormancy during the early November and late November, and became active thereafter.\ud
It was ascertained that both the contents of total sugar and starch were increased slowly during the dormant period. The total sugar increased rapidly since the budbreak occurred, the content of starch reached to maximum during the deep dormant period and decreased thereafter till the bud- break began. Besides, it was found that the bud dormancy was losely related to the nitrogen content of buds and shoots. The protein nitrogen showed no change untill dormant termination occurred, and them increased gradually to budbreak. However, the content of non-protein nitrogen decreased slightly during the period of deep dormancy and then increased rapidly till the budbreak began. When the shoot was treated with calcium cyanamide, the increment of total sugar and nitrogen towards the budbreak occurred earlier after pruning